Conventional hole saws include a cylindrical body having a circular series of saw teeth at one end and a mandrel including a shank attached to the opposite end wall of the cylindrical body. The shank is received into the chuck of an electric drill. The mandrel further includes a pilot drill which extends through the interior of the cylindrical body and past the saw teeth. The pilot drill thereby contacts the surface to be cut before the saw teeth in order to aid in the positioning of the hole saw.
Typically, hole saws include two or more clean-out slots which extend from slightly above the saw teeth toward the mandrel. The clean-out slots are useful in allowing sawdust to escape during the sawing process. This theoretically makes removal of the waste plug from within the interior of the hole saw easier.
In practice, it has been found that waste plugs are often difficult to remove from the interior of the hole saw. The slots do not allow sufficient sawdust to escape and the plug remains tightly bound within the interior of the hole saw. The waste plug is then usually removed by physically tapping the hole saw against an object or by trying to insert a thin object, such as a screwdriver tip, through one of the cleaning slots so as to push the waste plug out of the hole saw. Both of these methods are very unsatisfactory. Hole saws are fabricated from a relatively thin sheet stock which is not designed to take heavy forces along its side walls. Also, the screwdriver tips tend to tear and bend the hole saw walls. Additionally, if only one screwdriver is inserted into a hole, the waste plug tends to have a camming action which may wedge it even more tightly within the hole saw. The screwdriver can access only one slot at a time. As a result, the slug is forced in an outward direction at one slot opening and because there is a pilot bit extending through the axis of the slug, the opposite side of the slug moves in an opposite directly downwardly. The cup then has to be rotated 180 degrees to access the opposite slot in an attempt to force the opposite side of the slug outwardly of the cup. This procedure sometimes has to be repeated until the wedged slug is removed. This results in a frustrating, inconvenient and time consuming process.
In the past, various U.S. patents have issued relating to devices for removing slugs of material from the interior of circular hole saws or dies. For example, U.S. Pat. No. 2,433,058, issued on Dec. 23, 1947 to G. Mesaros describes a circular cutting and ejecting die in which a sleeve is freely mounted on the die and is adapted to engage the annular edge of the opening in the material produced by the cutting of the circular element therefrom. This serves to eliminate frictional engagement of the upper portion of the die therewith. The sleeve is apertured for permitting the lubrication of the confronting surfaces of the sleeve and die.
U.S. Pat. No. 4,652,185, issued on Mar. 24, 1987 to D. A. Malrick, describes a device for removing waste plugs from hole saws which includes a plug member positioned internally of a hole saw and retained therein by means of screws or other projections which extend outwardly through clean-out slots of the hole saw. The ring is grasped and forced downwardly causing the plug member to eject a waste plug from the hole saw.
U.S. Pat. No. 4,755,088, issued on Jul. 5, 1988 to J. Vajda, describes a tool for unjamming the material in a hole saw. This tool includes an adapter member constructed to be received within the interior of the cutter and provided at one end with an enlarged head for contacting the jammed material. The tool includes a slide hammer adapted to be interlocked with the other end of the adapter member for applying the force required to remove the adapter member and the jammed material from the interior of the hole saw cutter.
U.S. Pat. No. 5,035,548, issued on Jul. 30, 1991, to J. A. Pidgeon, teaches a hole saw driver and extruder which includes a flanged irregular bushing fitted through a corresponding irregular hole in the base of a conventional hole saw and which supports a cylindrical shank which extends from the back of the hole saw. Either the bushing or the shank is internally threaded. The collar is free to reciprocate on the shank and has pins projecting through corresponding holes through the base of the hole saw into the cup of the saw. When the collar is positioned away from the base of the hole saw, the pins extend only a short distance into the cup of the saw so as to permit the mandrel to be threaded deeply into the saw with the fingers on the end of the saw close to the saw base. When the collar is moved closer to the saw base, the pins extend deeper into the cup of the saw so as to block revolution of the mandrel fingers in the saw so that when the mandrel is rotated from in back of the saw, torque is transmitted to the saw for sawing. When the collar is moved away from the saw base, the collar pins are withdrawn from contact with the mandrel fingers and the mandrel is free to be threaded out through the hole saw to extrude any residual sawed material from within the saw.
U.S. Pat. No. 5,076,741, issued on Dec. 31, 1991 to J. M. Littlehorn, describes a plug ejecting hole saw which has no shoulder stop on the mandrel and extended threads on the mandrel so that after a hole is cut, the clutch is moved away from the saw. The saw is held from rotating and the mandrel is threaded further so that its end ejects the plug.
U.S. Pat. No. 5,435,672, issued on Jul. 25, 1995 to Hall et al., describes a hole saw with a plug ejection feature. The arbor of an ordinary commercially available hole saw is replaced. An arbor nut is threaded into the hole saw cup axial threaded inlet so as to convert the ordinary hole saw into a plug ejecting hole saw. The arbor and the arbor nut of the plug ejecting hole saw function as the arbor of an ordinary hole saw when used to drill the desired hole. When the drill rotation is reversed to a counterclockwise direction and the hole saw cup is held stationary, the arbor screws through the stationary arbor nut so as to eject the plug from the hole saw cup.
It is an object of the present invention to provide a faster, more convenient method and apparatus for removing debris from a hole saw cup.
It is another object of the present invention to provide a tool for the removal of debris from a hole saw cup which is adaptable to various sizes of such hole saws.
It is another object of the present invention to provide a tool for the removal of debris from a hole saw cup which provides rotational movement for aiding in the removal of slugs of material.
It is another object of the present invention to provide a tool for the removal of debris from a hole saw cup which facilitates easy gripping of the tool.
It is another object of the present invention to provide a tool for the removal of debris from a hole saw cup which is light in weight and suitable for compact storage.
It is a further object of the present invention to provide a tool for the removal of debris from a hole saw cup that is easy to manufacture, easy to use and relatively inexpensive.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.